The present invention relates generally to a method and associated apparatus for making a pattern for a lens opening in an eyeglass frame and deals more specifically with a pattern making method and apparatus for cutting a pattern from a blank in accordance with a set of coordinates defining a plurality of data points and collectively characterizing the size and shape of a lens opening.
The optical industry generally produces a pattern having the size and shape of a lens opening in an eyeglass frame for use as a guide in an edge grinding and contouring apparatus to peripherally edge grind an optical lens to the size and shape of the lens opening. The pattern is normally made by manually aligning a frame lens opening with a blank and fixturing the frame and the blank together to transfer the shape of the lens opening to the blank. Generally, the shape of the lens opening is transferred to a grid-like marking on the surface of the blank by tracing the outline of the inner periphery of the lens opening with some type of marker or other transfer device. The blank is then cut following the outline on the blank surface to form a pattern corresponding to the associated traced lens opening.
In order to produce an accurate optical lens from an associated pattern, it is critical that the alignment of the A axis and the mechanical center of the lens opening in the frame be properly aligned with the A axis and the mechanical center of the blank and accordingly, the mechanical center and A axis of a pattern cut from the blank. A scissors may be used to cut a blank made from a material such as plastic and the edges of the pattern smoothed by filing or grinding. Oftentimes a trial and error procedure is followed to remove inconsistences from the pattern to provide a better fit with a given frame.
Consequently, presently known methods and associated apparatus used to generate a pattern for a lens opening in an eyeglass frame are labor intensive, require a great deal of skill to carry out and are generally unsatisfactory to provide large quantities of patterns accurately and quickly.
It would be desirable therefore to have a method and apparatus for the production of patterns that are quickly and accurately cut from blanks and that overcome the drawbacks generally associated with other known methods and apparatus of pattern production.
An object of the present invention is therefore to provide a method and associated apparatus for the high volume production of accurately shaped and sized patterns for lens openings in eyeglass frames.
Another object of the invention is to provide apparatus that automatically and quickly fixtures a blank at a work station for cutting into a desired pattern.
A further object of the present invention is to provide a method and apparatus for automatically feeding blanks from a supply of blanks wherein the supply of blanks is in the form of a chain.
It is yet a further object of the present invention to provide a method and apparatus for cutting a pattern from a blank using coordinate information characterizing the size and shape of a lens opening in an eyeglass frame.